The present invention relates to a data recording controller, and more particularly, to a data recording controller for controlling recording operations in a data recorder that records data to a recording medium.
Data subjected to recording (original data) is normally not directly recorded on a recording medium. The original data undergoes a conversion, such as modulation. The converted data (write or record data) is then recorded on the recording medium. The conversion of the original data is performed to increase the recording density and to guarantee reliability.
For example, a recorder (DVD recorder) using a digital versatile disc (DVD), which is one type of optical disc, as the recording medium performs 8-16 modulation of the original data, to which a predetermined error correction code is added. Further, the modulated data undergoes non return to zero inverted (NRZI) conversion to generate write data.
The 8-16 modulation modulates 8 bits of data to 16 bits of data based on a predetermined conversion table. In the 16 bits of 8-16 converted data, there are two or more and ten or less zeros “0” between a pair of ones “1”. In accordance with a predetermined regularity, the NRZI conversion converts a string of data to data that is easily recorded. The 8-16 conversion and NRZI conversion increases the redundancy of the DVD write data compared to the original data. However, this facilitates determination of the appropriateness of the write data and the recording of the write data. Accordingly, data is recorded in a highly reliable manner.
In 8-16 modulation, multiple conversion tables having a plurality of 16 bit data conversion patterns for a single piece of 8 bit data are used. One of the conversion patterns is selected based on a conversion number assigned to the data modulated before the data that is subject to modulation. The conversion number is set by referring to a bit array of the data modulated before the modulation subject data.
In NRZI conversion, the modulated data depends on the value of the data immediately before the conversion. Accordingly, when converting original data to write data, the DVD recorder requires a conversion number and a conversion parameter for the data immediately before the conversion. Thus, the DVD recorder has a data recording controller that holds the conversion parameter whenever converting original data to use the parameter in the next conversion of original data. By sequentially providing such conversion parameters, the original data is continuously converted to write data while maintaining conversion regularity.
When recording new write data subsequent to write data that is already recorded on the recording medium, the continuity of the conversion parameters is lost at the point in which the two portions of write data are connected. Thus, in the prior art, when performing the next recording operation after the preceding recording operation, to prevent the irregularity of the conversion parameters from affecting the continuity of the write data, the termination of the recording operation after the writing of the write data is completed at a predetermined block position on the recording medium has been proposed. When doing so, dummy data (link data) is written after the final write data until reaching a predetermined block position in which the writing should be completed.
The recording (writing) operation of the DVD recorder will now be discussed.
In a DVD, a data recording position on the disc is managed using a series of sector numbers, the head address of which is 30000H. The “H” represents a hexadecimal. Data is recorded in sector units in correspondence with the address. One sector includes 2,048 bytes of data and a header added to the data. A single block (data block) includes 16 consecutive sectors and an inner parity and other parity, which are added to each of the 16 sectors. The outer parities included in a block are rearranged for each sector and recorded in a sector unit, which includes the inner parity and the outer parity.
In each recording sector, a synch code is added to the head of every 92 bytes of data. Then, the data is modulated to generate a physical selector corresponding to the address which head is 30000H. A unit of 92 bytes of data to which a synch code is added is referred to as a frame. A single physical sector includes 26 frames.
When completing the recording of DVD format data and restarting the recording of the DVD format data, the DVD recorder operates as shown in FIG. 1.
When recording data, a valid data write process and a link data write process are performed. Valid data refers to the write data generated by performing 8-16 modulation or NRZI modulation on the original data. In FIG. 1, the writing of the valid data temporarily ends at an intermediate position A, which is the ith block. When the writing of valid data is interrupted in such manner, link data (e.g., all “0”) is written from the write interruption position A to a predetermined position B. That is, link data is written to the section from the write interruption position A at the ith block to a write position B of the (i+2)th block, which is subsequent to an (i+1)th block. The writing (adding) of the next data starts from the write position B. In this manner, link data is added to write data in units of blocks Thus, even when the conversion is performed in an irregular manner, the additional recording of data is enabled without being affected by the irregularity. However, the writing of the link data when writing is interrupted decreases the storage efficiency of the recording section in the disc.